Info Boxes | SRCSET Errors

[backpackingseries]

Hi,

I am witnessing weird behaviour with the Info Boxes block. When I run my site via W3 validator, the Info Boxes returns a series of errors

Error: Bad value for attribute srcset on element [img](https://html.spec.whatwg.org/multipage/#the-img-element): Must contain one or more image candidate strings.

This is a problem when I use local media library images - screenshot below.

Any way I could avoid these validation code errors?

Kind regards,